The general aims of this research plan include the improvement of the treatment of childhood cancer through participation in organized clinical trials with fellow mwmbers of the Pediatric Oncology Group. To this end, the General Clinical Program, with the personnel required for maintenance of adequate protocol standards is described as well as the activity of the Hodgkin's Disease Committee which is chaired by Dr. Leventhal and with whom Dr. Kramer will be collaborating on a special project for assessing the value of chest CT scans in assessing disease severity at diagnosis and the speed with which remission is attained. The Radiation Oncology, Pediatric Surgery, and Pathology sections of this application also pertain to effective participation in Pediatric Oncology Group protocol studies. The Pediatric Oncology Group has an excellent record in effective submission of specimens to reference laboratories for immunologic and other studies in acute lymphocytic leukemia. With the availability of a library of monoclonal antibodies developed by Dr. Civin against myeloid differentiation antigens, the group is beginning to make progress in specific immunologic subclassification in nonlymphocytic leukemia as well and some of these may be important for prognosis. A frozen nonlymphocytic leukemia tissue bank has also been developed which will serve as a research resource for the group as a whole. The Nonlymphocytic Leukemia Reference Laboratory Program describes these projects. Dr. Graham has also developed a Methotrexate Reference Laboratory which is now functional and will address itself to the question of whether the level of drug achieved in the patients' red cells, chronically, over the course of therapy is an important variable in the outcome of antileukemic treatment. The multiplicity of projects, we feel, reflects the intense commitment of our faculty to our work within the Pediatric Oncology Group. With the small numbers of Pediatric Oncology patients admitted with any single diagnosis to an individual institution, it is clear that cooperative clinical research is required if significant advances are to be made.